Evidence of multiple pyrethroid resistance mechanisms in the malaria vector Anopheles gambiae sensu stricto from Nigeria

Awolola, T.S., Oduola, O.A., Strode, C., Koekemoer, L.L., Brooke, B. and Ranson, H. (2009) Evidence of multiple pyrethroid resistance mechanisms in the malaria vector Anopheles gambiae sensu stricto from Nigeria. Transactions of the Royal Society of Tropical Medicine and Hygiene, 103 (11). pp. 1139-1145. ISSN 0035-9203 DOI https://doi.org/10.1016/j.trstmh.2008.08.021

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Pyrethroid insecticide resistance in Anopheles gambiae sensu stricto is a major concern to malaria vector control programmes. Resistance is mainly due to target-site insensitivity arising from a single point mutation, often referred to as knockdown resistance (kdr). Metabolic-based resistance mechanisms have also been implicated in pyrethroid resistance in East Africa and are currently being investigated in West Africa. Here we report the co-occurrence of both resistance mechanisms in a population of An. gambiae s.s. from Nigeria. Bioassay, synergist and biochemical analysis carried out on resistant and susceptible strains of An. gambiae s.s. from the same geographical area revealed >50% of the West African kdr mutation in the resistant mosquitoes but <3% in the susceptible mosquitoes. Resistant mosquitoes synergized using pyperonyl butoxide before permethrin exposure showed a significant increase in mortality compared with the non-synergized. Biochemical assays showed an increased level of monooxygenase but not glutathione-S-transferase or esterase activities in the resistant mosquitoes. Microarray analysis using the An. gambiae detox-chip for expression of detoxifying genes showed five over-expressed genes in the resistant strain when compared with the susceptible one. Two of these, CPLC8 and CPLC#, are cuticular genes not implicated in pyrethroid metabolism in An. gambiae s.s, and could constitute a novel set of candidate genes that warrant further investigation.

Item Type: Article
Subjects: Q Science > QH Natural history > QH301 Biology
Q Science > QH Natural history > QH426 Genetics
Divisions: Biology
Date Deposited: 10 Mar 2016 14:30
URI: http://repository.edgehill.ac.uk/id/eprint/7304

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